libzonecfg/common/getzoneent.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
 */


/*
 * This module contains functions used for reading and writing the index file.
 * setzoneent() opens the file.  getzoneent() parses the file, doing the usual
 * skipping of comment lines, etc., and using gettok() to deal with the ":"
 * delimiters.  endzoneent() closes the file.  putzoneent() updates the file,
 * adding, deleting or modifying lines, locking and unlocking appropriately.
 */

#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <libzonecfg.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <assert.h>
#include <uuid/uuid.h>
#include "zonecfg_impl.h"


#define _PATH_TMPFILE   ZONE_CONFIG_ROOT "/zonecfg.XXXXXX"

/*
 * gettok() is a helper function for parsing the index file, used to split
 * the lines by their ":" delimiters.  Note that an entry may contain a ":"
 * inside double quotes; this should only affect the zonepath, as zone names
 * do not allow such characters, and zone states do not have them either.
 * Same with double-quotes themselves: they are not allowed in zone names,
 * and do not occur in zone states, and in theory should never occur in a
 * zonepath since zonecfg does not support a method for escaping them.
 *
 * It never returns NULL.
 */

static char *
gettok(char **cpp)
{
    char *cp = *cpp, *retv;
    boolean_t quoted = B_FALSE;

    if (cp == NULL)
        return ("");
    if (*cp == '"') {
        quoted = B_TRUE;
        cp++;
    }
    retv = cp;
    if (quoted) {
        while (*cp != '\0' && *cp != '"')
            cp++;
        if (*cp == '"')
            *cp++ = '\0';
    }
    while (*cp != '\0' && *cp != ':')
        cp++;
    if (*cp == '\0') {
        *cpp = NULL;
    } else {
        *cp++ = '\0';
        *cpp = cp;
    }
    return (retv);
}

char *
getzoneent(FILE *cookie)
{
    struct zoneent *ze;
    char *name;

    if ((ze = getzoneent_private(cookie)) == NULL)
        return (NULL);
    name = strdup(ze->zone_name);
    free(ze);
    return (name);
}

struct zoneent *
getzoneent_private(FILE *cookie)
{
    char *cp, buf[MAX_INDEX_LEN], *p;
    struct zoneent *ze;

    if (cookie == NULL)
        return (NULL);

    if ((ze = malloc(sizeof (struct zoneent))) == NULL)
        return (NULL);

    for (;;) {
        if (fgets(buf, sizeof (buf), cookie) == NULL) {
            free(ze);
            return (NULL);
        }
        if ((cp = strpbrk(buf, "\r\n")) == NULL) {
            /* this represents a line that's too long */
            continue;
        }
        *cp = '\0';
        cp = buf;
        if (*cp == '#') {
            /* skip comment lines */
            continue;
        }
        p = gettok(&cp);
        if (*p == '\0' || strlen(p) >= ZONENAME_MAX) {
            /*
             * empty or very long zone names are not allowed
             */
            continue;
        }
        (void) strlcpy(ze->zone_name, p, ZONENAME_MAX);

        p = gettok(&cp);
        if (*p == '\0') {
            /* state field should not be empty */
            continue;
        }
        errno = 0;
        if (strcmp(p, ZONE_STATE_STR_CONFIGURED) == 0) {
            ze->zone_state = ZONE_STATE_CONFIGURED;
        } else if (strcmp(p, ZONE_STATE_STR_INCOMPLETE) == 0) {
            ze->zone_state = ZONE_STATE_INCOMPLETE;
        } else if (strcmp(p, ZONE_STATE_STR_INSTALLED) == 0) {
            ze->zone_state = ZONE_STATE_INSTALLED;
        } else {
            continue;
        }

        p = gettok(&cp);
        if (strlen(p) >= MAXPATHLEN) {
            /* very long paths are not allowed */
            continue;
        }
        (void) strlcpy(ze->zone_path, p, MAXPATHLEN);

        p = gettok(&cp);
        if (uuid_parse(p, ze->zone_uuid) == -1)
            uuid_clear(ze->zone_uuid);

        break;
    }

    return (ze);
}

static boolean_t
get_index_path(char *path)
{
    return (snprintf(path, MAXPATHLEN, "%s%s", zonecfg_root,
        ZONE_INDEX_FILE) < MAXPATHLEN);
}

FILE *
setzoneent(void)
{
    char path[MAXPATHLEN];

    if (!get_index_path(path)) {
        errno = EINVAL;
        return (NULL);
    }
    return (fopen(path, "r"));
}

void
endzoneent(FILE *cookie)
{
    if (cookie != NULL)
        (void) fclose(cookie);
}

static int
lock_index_file(void)
{
    int lock_fd;
    struct flock lock;
    char path[MAXPATHLEN];

    if (snprintf(path, sizeof (path), "%s%s", zonecfg_root,
        ZONE_INDEX_LOCK_DIR) >= sizeof (path))
        return (-1);
    if ((mkdir(path, S_IRWXU) == -1) && errno != EEXIST)
        return (-1);
    if (strlcat(path, ZONE_INDEX_LOCK_FILE, sizeof (path)) >=
        sizeof (path))
        return (-1);
    lock_fd = open(path, O_CREAT|O_RDWR, 0644);
    if (lock_fd == -1)
        return (-1);

    lock.l_type = F_WRLCK;
    lock.l_whence = SEEK_SET;
    lock.l_start = 0;
    lock.l_len = 0;

    if (fcntl(lock_fd, F_SETLKW, &lock) == -1) {
        (void) close(lock_fd);
        return (-1);
    }

    return (lock_fd);
}

static int
unlock_index_file(int lock_fd)
{
    struct flock lock;

    lock.l_type = F_UNLCK;
    lock.l_whence = SEEK_SET;
    lock.l_start = 0;
    lock.l_len = 0;

    if (fcntl(lock_fd, F_SETLK, &lock) == -1)
        return (Z_UNLOCKING_FILE);

    if (close(lock_fd) == -1)
        return (Z_UNLOCKING_FILE);

    return (Z_OK);
}

/*
 * This function adds or removes a zone name et al. to the index file.
 *
 * If ze->zone_state is < 0, it means leave the
 * existing value unchanged; this is only meaningful when operation ==
 * PZE_MODIFY (i.e., it's bad on PZE_ADD and a no-op on PZE_REMOVE).
 *
 * A zero-length ze->zone_path means leave the existing value
 * unchanged; this is only meaningful when operation == PZE_MODIFY
 * (i.e., it's bad on PZE_ADD and a no-op on PZE_REMOVE).
 *
 * A zero-length ze->zone_newname means leave the existing name
 * unchanged; otherwise the zone is renamed to zone_newname.  This is
 * only meaningful when operation == PZE_MODIFY.
 *
 * Locking and unlocking is done via the functions above.
 * The file itself is not modified in place; rather, a copy is made which
 * is modified, then the copy is atomically renamed back to the main file.
 */
int
putzoneent(struct zoneent *ze, zoneent_op_t operation)
{
    FILE *index_file, *tmp_file;
    char *tmp_file_name, buf[MAX_INDEX_LEN];
    int tmp_file_desc, lock_fd, err;
    boolean_t exist, need_quotes;
    char *cp;
    char path[MAXPATHLEN];
    char uuidstr[UUID_PRINTABLE_STRING_LENGTH];
    size_t tlen, namelen;
    const char *zone_name, *zone_state, *zone_path, *zone_uuid;

    assert(ze != NULL);

    /*
     * Don't allow modification of Global Zone entry
     * in index file
     */
    if ((operation == PZE_MODIFY) &&
        (strcmp(ze->zone_name, GLOBAL_ZONENAME) == 0)) {
        return (Z_OK);
    }

    if (operation == PZE_ADD &&
        (ze->zone_state < 0 || strlen(ze->zone_path) == 0))
        return (Z_INVAL);

    if (operation != PZE_MODIFY && strlen(ze->zone_newname) != 0)
        return (Z_INVAL);

    if ((lock_fd = lock_index_file()) == -1)
        return (Z_LOCKING_FILE);

    /* using sizeof gives us room for the terminating NUL byte as well */
    tlen = sizeof (_PATH_TMPFILE) + strlen(zonecfg_root);
    tmp_file_name = malloc(tlen);
    if (tmp_file_name == NULL) {
        (void) unlock_index_file(lock_fd);
        return (Z_NOMEM);
    }
    (void) snprintf(tmp_file_name, tlen, "%s%s", zonecfg_root,
        _PATH_TMPFILE);

    tmp_file_desc = mkstemp(tmp_file_name);
    if (tmp_file_desc == -1) {
        (void) unlink(tmp_file_name);
        free(tmp_file_name);
        (void) unlock_index_file(lock_fd);
        return (Z_TEMP_FILE);
    }
    (void) fchmod(tmp_file_desc, ZONE_INDEX_MODE);
    (void) fchown(tmp_file_desc, ZONE_INDEX_UID, ZONE_INDEX_GID);
    if ((tmp_file = fdopen(tmp_file_desc, "w")) == NULL) {
        (void) close(tmp_file_desc);
        err = Z_MISC_FS;
        goto error;
    }
    if (!get_index_path(path)) {
        err = Z_MISC_FS;
        goto error;
    }
    if ((index_file = fopen(path, "r")) == NULL) {
        err = Z_MISC_FS;
        goto error;
    }

    exist = B_FALSE;
    zone_name = ze->zone_name;
    namelen = strlen(zone_name);
    for (;;) {
        if (fgets(buf, sizeof (buf), index_file) == NULL) {
            if (operation == PZE_ADD && !exist) {
                zone_state = zone_state_str(ze->zone_state);
                zone_path = ze->zone_path;
                zone_uuid = "";
                goto add_entry;
            }
            /*
             * It's not considered an error to delete something
             * that doesn't exist, but we can't modify a missing
             * record.
             */
            if (operation == PZE_MODIFY && !exist) {
                err = Z_UPDATING_INDEX;
                goto error;
            }
            break;
        }

        if (buf[0] == '#') {
            /* skip and preserve comment lines */
            (void) fputs(buf, tmp_file);
            continue;
        }

        if (strncmp(buf, zone_name, namelen) != 0 ||
            buf[namelen] != ':') {
            /* skip and preserve non-target lines */
            (void) fputs(buf, tmp_file);
            continue;
        }

        if ((cp = strpbrk(buf, "\r\n")) == NULL) {
            /* this represents a line that's too long; delete */
            continue;
        }
        *cp = '\0';

        /*
         * Skip over the zone name.  Because we've already matched the
         * target zone (above), we know for certain here that the zone
         * name is present and correctly formed.  No need to check.
         */
        cp = strchr(buf, ':') + 1;

        zone_state = gettok(&cp);
        if (*zone_state == '\0') {
            /* state field should not be empty */
            err = Z_UPDATING_INDEX;
            goto error;
        }
        zone_path = gettok(&cp);
        zone_uuid = gettok(&cp);

        switch (operation) {
        case PZE_ADD:
            /* can't add same zone */
            err = Z_UPDATING_INDEX;
            goto error;

        case PZE_MODIFY:
            /*
             * If the caller specified a new state for the zone,
             * then use that.  Otherwise, use the current state.
             */
            if (ze->zone_state >= 0) {
                zone_state = zone_state_str(ze->zone_state);

                /*
                 * If the caller is uninstalling this zone,
                 * then wipe out the uuid.  The zone's contents
                 * are no longer known.
                 */
                if (ze->zone_state < ZONE_STATE_INSTALLED)
                    zone_uuid = "";
            }

            /* If a new name is supplied, use it. */
            if (ze->zone_newname[0] != '\0')
                zone_name = ze->zone_newname;

            if (ze->zone_path[0] != '\0')
                zone_path = ze->zone_path;
            break;

        case PZE_REMOVE:
        default:
            continue;
        }

    add_entry:
        /*
         * If the entry in the file is in greater than configured
         * state, then we must have a UUID.  Make sure that we do.
         * (Note that the file entry is only tokenized, not fully
         * parsed, so we need to do a string comparison here.)
         */
        if (strcmp(zone_state, ZONE_STATE_STR_CONFIGURED) != 0 &&
            *zone_uuid == '\0') {
            if (uuid_is_null(ze->zone_uuid))
                uuid_generate(ze->zone_uuid);
            uuid_unparse(ze->zone_uuid, uuidstr);
            zone_uuid = uuidstr;
        }
        /*
         * We need to quote a path that contains a ":"; this should
         * only affect the zonepath, as zone names do not allow such
         * characters, and zone states do not have them either.  Same
         * with double-quotes themselves: they are not allowed in zone
         * names, and do not occur in zone states, and in theory should
         * never occur in a zonepath since zonecfg does not support a
         * method for escaping them.
         */
        need_quotes = (strchr(zone_path, ':') != NULL);
        (void) fprintf(tmp_file, "%s:%s:%s%s%s:%s\n", zone_name,
            zone_state, need_quotes ? "\"" : "", zone_path,
            need_quotes ? "\"" : "", zone_uuid);
        exist = B_TRUE;
    }

    (void) fclose(index_file);
    index_file = NULL;
    if (fclose(tmp_file) != 0) {
        tmp_file = NULL;
        err = Z_MISC_FS;
        goto error;
    }
    tmp_file = NULL;
    if (rename(tmp_file_name, path) == -1) {
        err = errno == EACCES ? Z_ACCES : Z_MISC_FS;
        goto error;
    }
    free(tmp_file_name);
    if (unlock_index_file(lock_fd) != Z_OK)
        return (Z_UNLOCKING_FILE);
    return (Z_OK);

error:
    if (index_file != NULL)
        (void) fclose(index_file);
    if (tmp_file != NULL)
        (void) fclose(tmp_file);
    (void) unlink(tmp_file_name);
    free(tmp_file_name);
    (void) unlock_index_file(lock_fd);
    return (err);
}